1. Field of the Invention
The present invention relates to a fabric yarn supply apparatus, and more particularly to a fabric yarn supply apparatus with dual feeding features, that is, one fabric yarn guide arm is for a long (i.e., low tension) fabric fabric yarn and for a short (i.e., high tension) fabric yarn.
2. Description of Prior Art
The trend of textile industry is the increasing need of a long fabric fabric yarn. The long fabric yarn is characterized in its low tension and fine texture. While a short fabric yarn is not able to be knitted as fabric with relatively large loop due to its high tension. Accordingly, manufacturer employs a technique, i.e., applies continuously a heated vapor to the short fabric yarn for processing the yarn before knitting, in order to lower the tension of the high tension yarn. Such a low tension yarn has a loop larger than the unprocessed one and as such it is required to trim the napping of the processed yarn. However, the processed yarn is able to knit a relatively high value added fabric. As an end, most manufacturers still prefer to process the long fabric yarn despite of the above additional processing. It is noted that the processed long fabric yarn has lost most of its tension. Further, an oxide with a lubricating grease (e.g., a greasy spot or powder) is formed on the surface of the processed long fabric yarn which made of many strands.
In FIG. 1, a prior art yarn supply apparatus is shown. The yarn path is described below. First, a yarn Y is led into a eye G1 of a yarn guide arm P and then through a yarn filtering gage E, a yarn brake B, an incoming yarn tension detecting arm D1, a lead-in yarn eye G2, a yarn supply drum F, a first pull-off eye G3, a second pull-off eye G4, and an outgoing fabric yarn tension detecting arm D2 to a circular knitting machine and needles (not shown). It is important to note that the yarn path from the eye G1 to the eye G2 is about vertical to the yarn path from the eye G2 to the yarn supply drum F. Further, the yarn Y is pressed between two components of the yarn brake B. Such prior art yarn supply apparatus is basically suitable to the short fabric yarn knitting due to its high tension and low operation speed (approximately five yards per second). However, as stated above, because the long fabric yarn is increasing its market share such an apparatus is unsatisfactory for the following reasons:
1. Operation speed is required to increase from about five yards per second to about one hundred yards per second. However, the oxide formed on the surface of the long fabric yarn is subject to be left on the elements of the apparatus which are contacted and especially on the components of the yarn brake B due to the contact area being the biggest among all contact areas. As a result, the smoothness of the yarn feed is disadvantageously affected because, for example, an adhesive substance left by the oxide of the long fabric yarn is formed between the components of the yarn brake B. This result greatly impedes the increase of operation speed and further lowers the quality of the fabric due to the uncontrollability of yarn tension. These are not desirable by the manufacturers.
2. The fabric yarn brake B is required for a short fabric yarn knitting. The components of the yarn brake B are further held together by means of a screw in some prior techniques for applying more force on the fabric yarn passed through therebetween. However, such technique is not required for the long fabric yarn knitting. As such, a detachment of the yarn brake B is required for the long fabric yarn knitting. Furthermore, it is required to mount the yarn brake B to the apparatus again for switching to the short fabric yarn knitting. Such a detachment-and-mounting switching procedure is really time-consuming and not cost effective. Moreover, it is troublesome to find a spare part immediately in the mounting procedure once a component of the yarn brake B was lost in the previous detachment procedure.
Thus, it is desirable to provide a yarn supply apparatus with dual feeding features to overcome the above drawbacks of prior art.